In general, since a crystalline epoxy resin has a rigid main chain skeleton and is multifunctional, the epoxy resin has high heat resistance. Therefore, such a resin is used in a field requiring heat-resistant reliability, for example, in an electrical and electronic field.
However, in some fields, molding such as casting molding is impossible for some applications unless a liquid composition is used. Therefore, use of the crystalline epoxy resin is restricted to an application using a solid material such as transfer molding, and the range of use of the crystalline epoxy resin is limited.
Conventionally, an epoxy resin used in liquid molding such as casting molding is a liquid epoxy resin, and cannot sufficiently meet a demand for improvement in physical properties of a cured product, such as heat resistance, that is strongly demanded in fields of adhesion, casting, sealing, molding, laminating, and the like in recent years. Therefore, liquefaction of a crystalline multifunctional epoxy resin that imparts physical properties of a cured product having high heat resistance is increasingly demanded.
As a method for producing such an epoxy compound, proposed is a method of epoxidizing an olefin in an acidic medium by a reaction of olefin-substituted isocyanurate using hydrogen peroxide as an oxidizer and a mixed catalyst containing tungstate or molybdate, a surfactant (using a quaternary ammonium salt as a phase-transfer catalyst), and phosphates or phosphonates as a catalyst (see Patent Document 1).
A method for producing an epoxy compound by a reaction of aqueous hydrogen peroxide solution with an olefin compound using a tungsten compound having an epoxidation performance as a catalyst in an acidic medium is disclosed, and aminomethylphosphonic acid is used as a promoter (see Patent Document 2).
Further, a method for producing an epoxy compound by a reaction of an olefin compound, hydrogen peroxide, a nitrile compound, and an alkaline substance in a solvent is disclosed (see Patent Document 3).